1. Field of the Invention
The present invention relates to a hydrodynamic coupling device for forming a torque transmission connection between a drive unit and a transmission, the coupling device having a first coupling area in which the hydrodynamic coupling device is couplable or coupled to the drive unit in a torque-transmitting manner and a second coupling area in which the hydrodynamic coupling device is couplable or is coupled to the transmission in a torque-transmitting manner. The present invention also relates to a method of making a hydrodynamic coupling device.
2. Description of the Related Art
Hydrodynamic coupling devices used in drivetrains in motor vehicles for hydrodynamic torque converters are principally constructed to be relatively extensively integrated in the transmission with respect to function and mechanical subassemblies. Usually, when constructing drivetrains, a hydrodynamic coupling device of this type is usually first combined with the transmission to form a subassembly. Then, the subassembly is added to and combined with a drive unit already installed on the chassis. Joining the subassembly of the coupling device and transmission to the drive unit is a relatively difficult undertaking because the installation space available between the hydrodynamic coupling device and the drive unit is very limited. In addition, assembly must be performed in a highly precise manner in order to minimize axial offsets or inclinations between a drive shaft of the drive unit and a driven shaft of the coupling device.
It is the object of the present invention to provide a hydrodynamic coupling device which simplifies the process of assembling the entire drive system.
This object is achieved by the present invention by a hydrodynamic coupling device for producing a torque transmission connection between a drive unit and a transmission, having a first coupling area in which the hydrodynamic coupling device is couplable or coupled to the drive unit in a torque-transmitting manner and a second coupling area in which the hydrodynamic coupling device is couplable or coupled to the transmission in a torque-transmitting manner. The hydrodynamic coupling device is coupled to the transmission in the second coupling area only for transmitting a driving/braking torque between the drive unit and transmission.
This arrangement for a hydrodynamic coupling device ensures that a torque-type coupling or interaction between the hydrodynamic coupling device and the transmission ultimately takes place only for the purpose actually provided for by the coupling device. Namely, for transmission of a driving torque or for transmission of a braking torque. There are no other torque-type couplings or interaction areas directly between the coupling device and the transmission. It is no longer necessary to first form a subassembly of the coupling device and transmission. Rather, the coupling device can be added to the drive unit as a separate subassembly before the transmission. Then, the transmission can be added by itself to the coupling device which is already installed. The transmission can be coupled to the coupling device so that a driving torque or braking torque can be transmitted between the coupling device and the transmission.
It is possible for the hydrodynamic coupling device to include an impeller wheel and a turbine wheel as well as a work fluid in a work fluid space, which provides a fluid torque coupling between the impeller wheel and the turbine wheel. It is also possible, in the second coupling area, to form only a torque-transmitting coupling between the turbine wheel and an input area of the transmission.
In an embodiment of the present invention, the hydrodynamic coupling device can be constructed to include a work fluid pump arrangement for supplying work fluid to the work fluid space and for discharging work fluid from the work fluid space. In this case, the work fluid pump arrangement is couplable or is coupled in a torque-transmitting manner with a subassembly which moves during operation, preferably, the impeller wheel or a subassembly in torque transmitting connection with the impeller wheel. The work fluid pump arrangement is also couplable to or is coupled to the drive unit or a subassembly associated with the drive unit.
As a result of this construction, the work fluid pump arrangement is still driven by a component or subassembly of the coupling device itself. However, support of the work fluid pump arrangement against this driving torque is no longer effected relative to the transmission, but is formed for the drive unit or a subassembly associated with the drive unit. A xe2x80x9csubassembly associated with the drive unitxe2x80x9d is any subassembly which can ultimately form a fixed torque supporting unit with the drive unit without the need for the transmission to be provided or installed beforehand. Accordingly, in principle, a vehicle chassis or other component of the vehicle can be considered xe2x80x9ca subassembly which is associated with the drive unitxe2x80x9d in a torque-supporting manner. For example, after the drive unit is fitted to the chassis it can, in principle, permit such support without the need for the transmission to be mounted beforehand. In other words, the torque support takes place without the need for a torque flow to be carried out via the transmission or other component of the transmission. It is possible, for example, for the work fluid pump arrangement to be integrated in the drive unit and put into operation through a drive shaft of the drive unit.
In a further embodiment, the hydrodynamic coupling device of the present invention is constructed so that it comprises a stator wheel which is rotatable on a supporting arrangement in a first rotating direction and is supported so as to be blocked against rotation in a second rotating direction opposed to the first rotating direction. The supporting arrangement can be couplable or coupled in a torque-transmitting manner to the drive unit or a subassembly associated with the drive unit. As previously discussed xe2x80x9ca subassembly associated with the drive unitxe2x80x9d may be included in the device.
It is also advantageous for the work fluid pump arrangement to be couplable or coupled via the supporting arrangement in a torque-transmitting manner to the drive unit or to the subassembly associated with the drive unit.
According to a further embodiment of the present invention, a hydrodynamic coupling device, especially a hydrodynamic torque converter, for transmitting/converting a driving/braking torque between a drive unit and a transmission, includes an impeller wheel, a turbine wheel, a stator wheel and/or a supporting arrangement and a work fluid pump arrangement. The impeller wheel is torque transmission connectable or is in torque transmission connection with the drive unit. The turbine wheel is torque transmission connectable or is in torque transmission connection with the transmission. The stator wheel is rotatable on a supporting arrangement in a first rotating direction and is supported so as to be blocked against rotation in a second rotating direction opposed to the first rotating direction. Optionally, a work fluid pump arrangement by which a work fluid can be supplied to a work fluid space and discharged from a work fluid space is provided. The work fluid pump arrangement is couplable or is coupled in a first pump area in a torque-transmitting manner to the impeller wheel or a component rotating therewith, and is couplable or is coupled in a second pump area in a torque-transmitting manner to a subassembly which essentially does not move with the impeller wheel during operation.
In a further embodiment of the present invention the supporting arrangement and/or the second pump area is coupled in a torque-transmitting manner to the drive unit or to a subassembly associated with the drive unit.
In this way, an at least partial decoupling of the hydrodynamic coupling device from the transmission by way of subassembly can be achieved, to facilitate the assembly of a whole system.
It is also possible that the torque transmission coupling of the work fluid pump arrangement and/or the supporting arrangement to the drive unit or to the subassembly associated therewith can be made before the torque transmission connection of the hydrodynamic coupling device with the transmission is made.
Preferably, torque transmission coupling of the work fluid pump arrangement and/or the supporting arrangement to the drive unit is done before the transmission is integrated into the drive system.
In a still further embodiment of the present invention, a hydrodynamic coupling device such as that generally described above can be constructed so that the supporting arrangement has a first supporting element and a second supporting element. The first supporting element is fixedly couplable or is fixedly coupled to the drive unit or subassembly associated therewith. The second supporting element is connected to or is integral with the first supporting element and supports the stator wheel. The second supporting element forms or has a part of the work fluid pump arrangement.
The stator wheel support can be part of the coupling device. Integration of the work fluid pump arrangement in the area of the stator wheel support is achieved by a subassembly. This results in two particularly advantageous effects. First, the work fluid pump arrangement subassembly is fully integrated in the coupling device itself, so that the coupling device itself can form a functional unit. Second, support of this work fluid pump arrangement with respect to torque is carried out by means of the same supporting arrangement which also provides support of the stator wheel. This leads to an appreciably simplified design.
In a further embodiment of the present invention, a pump space is formed at the second supporting element, a first pumping area and, optionally, a second pumping area is provided in this pump space, wherein at least the first pumping area can be driven to movement by the impeller wheel in order to discharge work fluid from the work fluid space or to supply work fluid to the work fluid space.
It is advantageous for a fluid channel arrangement to be provided in the second supporting element, wherein the work fluid can flow toward and away from the pump space through this fluid channel arrangement.
When the turbine wheel and an area of a housing of the hydrodynamic coupling device connected with the impeller wheel are held by the supporting arrangement relative to the drive unit in an axial direction with respect to an axis of rotation of a drive shaft of the drive unit and the area of the housing is preferably pressed against the drive shaft, the supporting arrangement can assume a further function, namely, to hold various components axially.
For this purpose, a first driver arrangement is provided in the area of the housing. When the supporting arrangement is coupled to the drive unit or to the subassembly associated therewith, the first driver arrangement is held in a torque-transmitting positive engagement with a second driver arrangement which is rotatable with the drive shaft. These two driver arrangements then necessarily remain engaged by the axial support of different subassemblies of the coupling device. This axial support is necessarily supplied by the supporting arrangement. It is therefore impossible for these two driver arrangements to disengage from one another axially.
It is possible for the supporting arrangement to perform another function as it forms at least a part of a housing of the hydrodynamic coupling device comprising the work fluid space.
In a further embodiment of the present invention the turbine wheel is in torque transmission connection with a driven member. Preferably, the driven member is a driven shaft of the hydrodynamic coupling device. The driven member can be brought into torque transmission connection with a transmission input member for producing the torque transmission connection between the drive unit and the transmission. Preferably, the transmission input member is a transmission input shaft. In order to be able to achieve vibration damping in the coupling device itself in case of torsional vibrations, it is suggested that the turbine wheel be in torque transmission connection with the driven member by means of a torsional vibration damping arrangement.
Further, the coupling device can have a lockup clutch arrangement by means of which a torque transmission connection can be produced between a drive shaft of the drive unit and the driven member. This at least partially locks the operating mechanism comprising impeller wheel and turbine wheel. Preferably, a torsional vibration damper arrangement is operatively incorporated into the coupling device.
The present invention further relates to a drive system comprising a drive unit, a transmission and a hydrodynamic coupling device according to the invention. The present invention also relates to a process for assembling a drive system having a drive unit, a transmission and a hydrodynamic coupling device according to the invention. The process includes the following steps:
a) joining the drive unit and hydrodynamic coupling device to form a constructional unit,
b) and then joining the constructional unit to the transmission.
Preferably, step a) includes producing a torque transmission connection between a drive shaft of the drive unit and a first coupling area of the hydrodynamic coupling device while producing a torque transmission coupling between at least one of a supporting arrangement supporting a stator wheel of the hydrodynamic coupling device and a first pump area of a work fluid pump arrangement of the hydrodynamic coupling device; and the drive unit or a subassembly associated therewith.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of the disclosure. For a better understanding of the invention, its operating advantages, and specific objects attained by its use, reference should be had to the drawing and descriptive matter in which there are illustrated and described preferred embodiments of the invention.